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Unread 01-26-2013, 04:52 PM   #1
gazzo
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hot coil?

Hey folks, probably a dumb question but should my coil get super hot? I been getting hard starts, cranking but no fire. It tries to go after I release the key but won't run on.

The coil is getting way too hot to touch, does this sound like a bad coil to you?

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Unread 01-27-2013, 10:40 AM   #2
dslywalker
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could be your ignition module.If its trying to start after you release the key.Maybe its getting the coil hot or bad coil.
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Unread 01-27-2013, 04:41 PM   #3
gazzo
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that

Quote:
Originally Posted by dslywalker View Post
could be your ignition module.If its trying to start after you release the key.Maybe its getting the coil hot or bad coil.
Thanks I have a spare one around somewhere which I'll try. Yesterday I swapped coils with the one from the eight and it got hot too. They both got real hot when we were driving around the dunes yesterday and the problem continued in the 7. Just about to bone up on the nutter bypass and see how that goes. I'll try anything at this point, this problem has us all stumped.
1. Cranks but sometimes won't start, particularly when hot
2. Loads of fuel so most likely not that
3. Tries to fire when you release the key but won't run on.
4. Won't fire at all when rolling down a long hill in 3rd. Ignition on of course.
5. Then out of the blue she''ll fire right up like nothing ever happened just to give me the shiz.
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Unread 01-27-2013, 05:01 PM   #4
86cj74.2L
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Make sure you have reduced voltage to the plus terminal of the coil. It should not be 12+ volts when engine is running. It should be between 6v and 9v.

Or a dim bulb using a test light when comparing the brightness to reading across the battery terminals.
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Unread 01-27-2013, 05:08 PM   #5
pman
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Gazzo, I had the exact issue (hard starts, not starting at all occassionally, wanted to start when releasing the key) on my wagon not long ago. Turned out to be the pickup coil in the dizzy. May not be the issue but worth a look.
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Unread 01-27-2013, 05:32 PM   #6
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Thanks guys, I have a meter down in the shed, I'll check it out when I reckon the battery's back up to speed. Gave it a workout yesterday for sure, good old Optima cranks like the bejeezes.
Pman how can I test the pick up coil?
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Unread 01-27-2013, 06:34 PM   #7
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Gary, my TSM didn't have test procedures for the V8 (or I6 for that matter). It did call for testing the resistance at the pickup coil on the 4 banger (I'm assuming HEI) with an ohmeter and vacuum pump. The part was cheap (under 10 dollars US), so I simply replaced it, and the problem was fixed.
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Unread 01-27-2013, 06:36 PM   #8
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Quote:
Originally Posted by gazzo
Thanks guys, I have a meter down in the shed, I'll check it out when I reckon the battery's back up to speed. Gave it a workout yesterday for sure, good old Optima cranks like the bejeezes.
Pman how can I test the pick up coil?
I'd concentrate on a replacing the ICM. Can you borrow one to use to troubleshoot? If you have a duraspark ignition now is your time to consider something better. The Borg Warner ICM's know one is calling junk............

The pickup coil in the dizzy can be ohmed to test but I don't know the specs.

A good way to test a coil is to momentarily ground (as in really fast) the coil with the ignition on and the green wire from the ICM removed. It should produce a spark when you remove the ground.

It seems your ICM may be shorted and grounding the coil all the time. Since it only tries when you turn off the key.

If I got it right.

Edit. Remove your ICM and see if its melted in the back side.
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Unread 01-28-2013, 05:01 AM   #9
gazzo
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Quote:
Originally Posted by pman View Post
Gary, my TSM didn't have test procedures for the V8 (or I6 for that matter). It did call for testing the resistance at the pickup coil on the 4 banger (I'm assuming HEI) with an ohmeter and vacuum pump. The part was cheap (under 10 dollars US), so I simply replaced it, and the problem was fixed.
Thanks pman you are THEman. That was it! Pesky pick up coil. I went for a run down the beach and she conked out again, started after a little rest then conked again a few minutes up the beach. I went and got the 8 and pulled the dizzies and swapped them out, baddabing, started first crank! One happy boy. I found the pickup plate assembly really wobbly and floppy in the 7's distributor, just didn't look right. The one from the 8 wasn't much better but she fired so thats what matters. Thanks again for taking time to reply to my post.

Quote:
Originally Posted by 86cj74.2L View Post
I'd concentrate on a replacing the ICM. Can you borrow one to use to troubleshoot? If you have a duraspark ignition now is your time to consider something better. The Borg Warner ICM's know one is calling junk............

The pickup coil in the dizzy can be ohmed to test but I don't know the specs.

A good way to test a coil is to momentarily ground (as in really fast) the coil with the ignition on and the green wire from the ICM removed. It should produce a spark when you remove the ground.

It seems your ICM may be shorted and grounding the coil all the time. Since it only tries when you turn off the key.

If I got it right.

Edit. Remove your ICM and see if its melted in the back side.
Thanks to you too Sir. You're on the same page as pman. So now I know it's the dizzy it's time to go shopping. The big question is do I go DUI or MSD (6)?
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Unread 01-28-2013, 05:55 AM   #10
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Quote:
Originally Posted by gazzo View Post
Thanks pman you are THEman. That was it! Pesky pick up coil.
Woot! Woot! Even I get lucky every now and then! Glad she's up and running!

Edit: Gary, you do know you can replace the pickup coil instead of buying a whole new dizzy, right? But I'm with ya, HEI all the way when possible!
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Unread 01-28-2013, 11:55 AM   #11
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I'm partial to the motorcraft distributor.

A DUI replaces your entire ignition system.

A MSD6 only replaces your spark box (ICM) the duraspark thing. You will still need to use a OEM distributor.

What is loose? The pickup????? Can it be tightened???
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Unread 01-28-2013, 01:44 PM   #12
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As someone who's had a stock Duraspark, a "team rushed" one, then a recurve on the advance of said dizzy who then replaced it with a D.U.I., I can tell you that there's no comparison.

If I were to do it all over again from a budget perspective, I'd recurve my Duraspark. I'd do the "stealth HEI" using a Dyno-Mod module from Performance Distributors along with one of their e-core coils.

I wouldn't waste money on the CDI boxes. It doesn't matter how hot the spark is, it needs to fire at the right time first.

Just my two cents...


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Unread 01-29-2013, 05:59 PM   #13
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Wow, Shawn, I headed off on the tangent that is this: http://www.jeepforum.com/forum/f8/he...curve-1238634/ that you linked. Cripes that goes a long way into it. I have read it before and love that level of depth in a thread.

You say "no comparison" between DUI and the other "easy mods". I'm a bit simple, can you explain no comparison to me, part of me thinks it is a no brainer and the other part thinks they're so close it's not worth bothering about doing the DUI conversion. I don't know whether I want to put budget price before quality with this part so do you think a DUI diz would be money well spent when compared with the time involved in doing the stealth route? DUI for my Jeep comes in at $299USD plus some other small items (leads etc) so that seems doable to me without telling the "Interior Minister" of course.

86, the whole plate is really loose and flopping about. I have another diz here in my shop which came with the white Overlander I sold to my friend. It too is a bit loose but nothing compared to the one out my 7. On closer inpection on the bench it doesn't look like something that can be tightened, it's all pins and those grip-washer retainers.

With the diz out of my CJ8 this thing hauls azz down the beach and the 150k highway run back home, no vac advance connected either by the way (forgot). I didn't even put the timing light on it after I dropped the diz in. I can only imagine what she'd be like all set up properly as one would do after reading that thread.

Thanks for your help guys.
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Unread 01-29-2013, 06:24 PM   #14
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My stealth HEI is made from junkyard parts. The modules I got all say GM on them. It cost practically nothing to make. And in a lot of different vehicles. (Using a standard stock OEM GM module)

A motorcraft dizzy here costs 54 to 70 US dollars.

A DUI may have higher quality mechanical parts then a reman motorcraft distributor. But the reman motorcraft in Grammys CJ is around 14 or 15 years old now and has at least 60,000 miles on it. And it came with the better advance curve over her stock unit.

My half cent.
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Unread 01-29-2013, 06:29 PM   #15
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http://www.crtperformance.com/html/jeep_hei_s.html

These work. I found i didnt need to open the gap as much as they said and you need to use a decent feed (not the resistive wire)
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